Highlights
- •The intra-operative observation of AMR usually falls into a pattern of “all or nothing”, but AMR seems to contain more information that could improve surgical results.
- •The appearance and observation of pre-decompression instability of AMR monitoring made a positive impact on the surgical outcomes of MVD surgeries.
- •The timely notification of the PDI advent improved the surgical outcomes of MVD surgery by increasing the electrophysiological relief rate and reducing the incidence of neurological dysfunction.
Abstract
Background
In microvascular decompression (MVD) surgery, abnormal muscle response (AMR) monitoring
was utilized to confirm sufficient decompression. However, the AMR seems to contain
more information that could improve surgical results.
Method
Patients’ records of HFS treated with MVD under AMR monitoring, from January 2018
to December 2019 in our centre, were retrospectively reviewed. MVD procedures were
performed via a suboccipital retrosigmoid approach, and AMR monitoring was performed.
Pre-Decompression Instability (PDI) of AMR before the final decompression, including
amplitude inconsistency and waveform chaos, was inspected and notified to the surgeon.
Result
165 cases were found with full follow-up data. In these cases, PDI was recognized
in 144 cases. And in the remaining 21 cases, the AMR disappeared abruptly or continued
to exist to the end of the MVD surgery. When PDI appeared, the rate of electrophysiological
relief was significantly higher (91.7 % vs 66.7 %, P = 0.001). In cases with PDI appearance
during MVD procedure, the rate of neurological dysfunction was lower (13.2 % vs 38.1 %,
P = 0.004). The relief rate the PDI group tended to be higher without statistical
significance.
Conclusion
The appearance and observation of pre-decompression instability of AMR monitoring
made a positive impact on the surgical outcomes of MVD surgeries. The advent of PDI
indicates that the key step of the procedure has arrived. The timely notification
of the PDI advent improved the surgical outcomes of MVD surgery by increasing the
electrophysiological relief rate, reducing the incidence of neurological dysfunction,
and possible elevation of the relief rate. Therefore, continuous intra-operative communication
between the surgeon and electrophysiological monitoring staff should be encouraged.
Keywords
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Article info
Publication history
Accepted:
August 4,
2022
Received:
March 20,
2022
Identification
Copyright
© 2022 Elsevier Ltd. All rights reserved.